> Although, it's very possibly a legacy of planned obsolescence (the good cost-saving kind) where the engine would last 200k so the rest of the car was only made to last 200k as well.

I think this is the answer. If a critical component of the car only lasts X miles, then building any other piece to last more than X miles is pure waste. As counterintuitive (and annoying) as it might seem, having all the parts of the car fail around the same time actually indicates that it was engineered perfectly.